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<title>无标题文档</title>
<script>
	var num=10;
	
	switch(true){
		case num=='10'://等号会将字符串先转换成数字然后再比较
			alert(1);
			break;
		case num>0 && num<10:
			alert(2);
			break;
		case num>10 && num<20:
			alert(3);
			break;
		default:
			alert('other');	
		
	};
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